I've seen really cheap tires with directional arrows pointing both ways. One way for front mounting and the opposite for rear. Usually you can tell by the tread patterns angleing out from the center in V-like patterns. Water dispersal and treadwear are affected. The latter by tread flex. What most people call cupping is wear associated with tread flex. Flex at the treads.

I've seen really cheap tires with directional arrows pointing both ways. One way for front mounting and the opposite for rear. Usually you can tell by the tread patterns angleing out from the center in V-like patterns. Water dispersal and treadwear are affected. The latter by tread flex. What most people call cupping is wear associated with tread flex. Flex at the treads.

Not just cheap ones. I just installed an Avon AM26 that was listed by the vendor as a rear (120\80-17) but a lot of the Pacific Coast guys use these on the front. Tire arrived with arrows for both Front Rotation and Rear Rotation.

The tread splice is also a factor in mounting direction aside from tread pattern....i.e. Dunlop K81's are mounted in opposite direction front and rear despite the pattern being symmetrical. Avon has a good tire reference that explains this at http://www.avonmoto.com/download/Tir...rConsumers.pdf
and here is a quote from it...

Tire manufacturers spend millions of dollars designing tires and they design them to work in one direction for a reason so they put direction indicators on them to be sure they are mounted for best performance, safety and mileage.
Most riders probably couldn't tell the difference just by the handling but the makers have spent countless hours testing minor details of the performance of the tire.

Come on now, that is all a conspiracy so we will not run car tires on our bikes

A tire should turn only in one direction (if it's a dirt bike tire it really doesn't matter) Many people who install a rear tire on the front reverse the direction. That does not make sense. Unless your bike is really weird, both tires turn in the same direction and that is what counts. I have (sadly) a front wheel drive transportation car, and because the front tires do everything, they wear out noticeably faster than the back tires. Every once in a while I switch places with the front and back tires (on the same side of the car) to even out the wear, check the brakes, etc. The point is, front or rear, the tires turn in the same direction. Same thing on a bike. You should not mount a tire backwards, as some of them can start to come apart from rolling the wrong way because of the way the plies are designed. If you put a rear tire on the front, put it on in the same direction as you would if it were going in the back.

If you put a rear tire on the front, put it on in the same direction as you would if it were going in the back.

Wrong. A tire mounted on the rear of a motorcycle gets stressed in the opposite direction vs a front tire.
The rear is stressed by acceleration, while the front tire stress is predominately from braking.
If you choose to mount a "rear tire" on the front, it should be mounted "backwards".

Wrong. A tire mounted on the rear of a motorcycle gets stressed in the opposite direction vs a front tire.
The rear is stressed by acceleration, while the front tire stress is predominately from braking.
If you choose to mount a "rear tire" on the front, it should be mounted "backwards".